Ignition timing confusion, please help

[emanaresi]

So, I recently "finished" rebuilding a cb-1 that I recently picked up.  I am a little confused by the factory manual that I have.  When I check the timing with my light connected to #1 or #4 I get the F mark lined up.  But if I check with #2 or #3, I do not get the F mark lined up.  The book says that the F should be lined up when on # 2 or #3.  What has been your experience?